INTERSTATE and foreign workers are pilfering high paying jobs on Sydney's construction sites because there's not enough homegrown tradies to handle the massive road and rail building boom.

That's the view of Deputy Premier John Barilaro, who's warned projects wrapped up in the state's planned $73.3 billion of infrastructure spending over the next four years could be jeopardised by the chronic skills shortage.

"There's a threat if we don't build the workforce, we won't get some of these projects off the ground," Mr Barilaro said.

The former chippie is hellbent on smashing the stigma vocational education and training (VET) is the poor cousin to university academia.

Nine out of 10 occupations predicted to have the greatest jobs growth in the next five years are within the vocational sector, according to a Skilling Australia Foundation report.

Mr Barilaro was at the site of the future NorthConnex tunnel on Friday morning, lauding newly certified specialist concreters required to build a nine kilometre tunnel linking the M1 Pacific Motorway at Wahroonga to the Hills M2 Motorway at West Pennant Hills.

One of the tradesmen being recognised was shotcreter Chris McKervey, 37, whose job it is to line the tunnel with concrete spray "to stop rock falling down and hitting cars when they're driving through".

Experienced shotcreters earn $212,000 a year and yet they're in short supply.

So much so Mr McKervey, who's been working underground for 13 years, has been drafted to work in tunnels from Lane Cove to Barrow Island off the Pilbara coast of Western Australia.